Lenticular images include an array of cylindrical lenses (or lenticules) in a lenticular material and a sequence of spatially multiplexed images that are viewed through the lenticular material so that different ones of the multiplexed images are viewed at different angles by the viewer. One image effect produced by the lenticular image is a depth or stereoscopic image where the lenticules are oriented vertically and one eye views one image of a stereo pair or sequence from one angle and the other eye views another image from the stereo pair. Another image effect is a motion image where different images in a motion image sequence are viewed by both eyes, while changing the angle at which the image is viewed. In this image effect the lenticules are oriented in the horizontal direction and the lenticular material is rotated about the long axis of the lenticules. Other effects that combine these two effects, or form collages of unrelated images that can be viewed from different viewing angles can be provided.
It has been proposed to create stereoscopic images by providing a lenticular material having a color photographic emulsion thereon. The stereoscopic images are exposed onto the lenticular material by a laser scanner and the material is processed to produce the lenticular image product. See for example, U.S. Pat. No. 5,697,006 issued Dec. 9, 1997 to Taguchi et al.
The image that is exposed on the lenticular material must be very precisely positioned under each lenticule. If the separate image lines produced by the writing laser beam of the laser scanner and the lenticules on the material are not aligned parallel, the resulting skew misalignment will degrade the image quality. There is a need therefore for an improved manufacturing process for making lenticular image products from lenticular material of the type having a lenticular lens array coated with photographic emulsion.
The following patents disclose various arrangements for aligning a lenticular overlay with a lenticular print which do not address the problem of aligning a writing laser beam with the lenticules of a photosensitive lenticular material.
U.S. Pat. No. 5,729,332, issued Mar. 17, 1998, inventors Fogel et al.
U.S. Pat. No. 5,633,719, issued May 27, 1997, inventors Oehlbeck et al.
U.S. Pat. No. 5,699,190, issued Dec. 16, 1997, inventors Young et al.
U.S. Pat. No. 5,424,553, issued Jun. 13, 1995, inventor Morton.
It is known to scan a non actinic laser beam across a lenticular array in a direction perpendicular to the axes of the lenticules, and to sense the deflection of the beam by the lenticules to produce an output clock for modulating a writing laser beam. See U.S. Pat. No. 5,681,676, issued Oct. 28, 1997 to Telfer et al.
It is one object of this invention to provide a method and apparatus for detecting and/or measuring lenticular skew relative to the writing laser beam for the purpose of printing accurate images on the material. It is another object of the invention to provide a method and apparatus for minimizing skew during manufacture of a lenticular image product.